This invention relates to platform mounting of horn antenna assemblies and more particularly to apparatus for enabling precise leveling of a horn antenna assembly that is mounted on a platform.
One known arrangement for mounting a horn antenna assembly on a platform comprises a first member that is a circular I-beam member and a second member that is a hexigonally shaped I-beam member. The first member is bolted to the top of the platform. The second member is set on top of the first (circular) member. The horn antenna assembly is attached to and located in the central opening in the top member. The lateral position of the two members is fixed by wheels on outboard flanges of the top member. The wheels contact the circumference of the first member. Alignment of the antenna is achieved by rotating the hex-shaped member on top of the circular member. The alignment is maintained with clamped compression bars which create a binding force between the two stacked members. It has been found that there can a rotational misalignment between the top and bottom members which reduces the precision and repeatability of an associated alignment procedure. This problem is compounded when the rollers are removed from the top member. Another prior art mounting structure for a horn antenna assembly comprises a rotatable ring member having an I-beam shaped cross section and a plurality of support members that are bolted to the top of a platform. The support members have extensions or arms thereon that extend into the openings in the ring shaped I-beam for suspending it above the platform. A compression band that extends around the circumference of the I-beam is supported by the arms. Alignment of the antenna is accomplished by rotating the ring on the support members. The alignment is maintained with the compression bands. It has been found that tightening the compression ring causes the antenna to move out of alignment. One method of leveling the antenna assembly along a horizontal axis thereof is to place shims under selected points around the fixed member. This technique is time consuming and does not provide repeatable results. Another technique for leveling the antenna in the horizontal plane is to adjust the position of the support platform. This approach also is unsatisfactory in that it does not provide repeatable results.
An object of this invention is the provision of improved apparatus for leveling a suspended antenna assembly along an axis of rotation thereof.